Spark-plug.



F. F. THOMASSON.

SPARK PLUG.

` APPLICATION FILED APR. 24| |9I7 v 1,298,601. Patented Mar. 25,1919.

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-Aamr/Q/Mu v I Br A 3 Arron/ms I' UNITED sTATEs PATENT oEEroE.

FREDERICK E. TrioMAssoN; or EoI'sE, IDAHO.

SPARK-PLUG.

Specification of Letters Patent.

Patented Mar. 25, 1919.

Application illed April 24, 1917. Serial I'ol 164,143.

"To all Awhom it may concern:

Be it known-that I, FREDERICK F. THOM- AssoN, a citizen of the United States, and a resident of the city of Boise, in the county' of Ada and State of Idaho, have invented a -new and Improved Spark-Plug, .of which the following is a full, clear, and exact description.

This invention relates to an ignition device for internal combustion engines, and has to deal particularly with a jump spark plug.

The invention has for its general objects to improve the construction of devices of this :character so as to be'reliable .and efficient in use, and comparatively simple and inexpensive to manufacture, and so designed as to insure ready ignition' of a priming charge of gasolene, as well as to enable the electrodes to be readily adjusted to obtain the rproper spark gap.

vA more `specific object of the invention is the provision of a spark plug which is formed with a head at its inner end that performs the double function of acting as a shield to prevent lubricant from being thrown on the electrode, and to .act as shallow panrto receive a priming charge of gasolene whereby such charge is held in close proximity, say inch, to the igniting spark.

the head of the spark plug, and the other- "ger lof- 'a short circuit connection being Further specific objects are to so arrange fone of the v'electrodes that it can be easily adjusted or renewed by being screwed into electrode has its sparking point bent laterally so that oil collected on such electrodes will drip therefrom at a point to one side-of the other electrode,`so.that there isino dan- 'the spark plug.

Fig. 2 isa sideview thereof. FigB vis anenl'arged section on ,the line 3.3 l igfll I y tained clear.

Referring tothe drawing l designates the shell or body of the electrode which has a chamber 2 in which is clamped the porcelain bushing 3 that carries the central electrode 4. The inner end of the shell or body 1 is formed with a head 5 united with the shell by oppositely disposed connecting portions 6, so that between the connecting portions 6 ports 7 will be provided for permitting the compressed gas to enter the spark plug and the flame to pass out of the latter into the cylinder. The head 5 has a central threaded opening 8 in which is screwedthe electrode 9, the lower` end 10 ofwhich is noncircular so that by means of a pair of pliers Ithe bottom electrode can be adjusted with respect to the upper electrode 4 for obtaining the right spark gap, and furthermore the lower electrode can thus be easily removed for cleaning or renewal.

The head 5 performs two functions in addition to acting as a support for the elecltrode 9. The inner surface of the head' s concave so as to constitute a pan 11 out of which rises the electrode 9. This panserves to retain a charge of priming gasolene and `hold it in close proximity to the spark, the

gasolene being supplied through an ordinary priming device 12 attached to the side of the spark plug. The other function of the head is the protection it affords against lubricant from being :thrown ona the electrodes by the reciprocation ofV the engine piston.

Lubricant 1S likely to collect on the upper electrode by being carried with a vaporlzed fuel into the spark plug, and in order to prevent a shortcircui-ting drop of lubricant to form between the electrodes when the engine is idle, the upper electrode has its lower end bent laterally so as to be out of vertical alinement with the lower electrode, and consequently lubricant will drop off the upper electrode at a point to one side of the lower electrode so that the spark From the foregoing description taken in gapwill be mainconnection with the accompanying draw'- ings, the advantages of the construction and method of operation willbe readily .understood by those skilled `in the art to which the invention pertains, and while I have described the principle of operation together with the apparatus, which I now consider to be the best embodiment thereof, I desire to have it understood Athat the apparatus shownV is merely illustrativejand that such changes may be made When desired as are within the scope of they appended claims.A

Having thus described my invention I claim as new, and desire to secure by Letters Patent,

1. A spark plug comprising a body havi ing a pan-shaped head at its inner end and provided with lateral ports, an electrode grounded on the head and disposed' within the body at a point between the ports, an insulation bushing in the body, an electrode in the bushing and arranged iny coperative relation with the first-mentioned electrode to forni a spark gap, and means for supplying a priming Charge Of fuel t0 the body `for filling the said pan. i

2. A spark plug comprising ahollow body having a'pan-shaped head at its inner end and providedwith lateral ports,` an electrode carried 'by the panand extending up- Wardly therefrom, with its upper end disposed between the ports and above the bot- '.tom of the latter, ,an insulation bushing in the said body,` antelectrode in the bushingI 

